"And how is one a noble one with developed faculties? There is the case where, when seeing a form with the eye (&tc.), there arises in a monk what is agreeable, what is disagreeable, what is agreeable & disagreeable. If he wants, he remains percipient of loathsomeness in the presence of what is not loathsome. If he wants, he remains percipient of unloathsomeness in the presence of what is loathsome. If he wants, he remains percipient of loathsomeness in the presence of what is not loathsome & what is. If he wants, he remains percipient of unloathsomeness in the presence of what is loathsome & what is not. If he wants — in the presence of what is loathsome & what is not — cutting himself off from both, he remains equanimous, alert, & mindful.

"And how is it, bhikkhus, that by protecting oneself one protects others? By the pursuit, development, and cultivation of the four establishments of mindfulness. It is in such a way that by protecting oneself one protects others.

"And how is it, bhikkhus, that by protecting others one protects oneself? By patience, harmlessness, goodwill, and sympathy. It is in such a way that by protecting others one protects oneself.- Sedaka Sutta [SN 47.19]

It's good for a monk if, at the appropriate times, he remains percipient of loathsomeness in the presence of what is not loathsome. It is good if, at the appropriate times, he remains percipient of unloathsomeness in the presence of what is loathsome... percipient of loathsomeness in the presence of what is not loathsome & what is... percipient of unloathsomeness in the presence of what is loathsome & what is not. It is good if, at the appropriate times — in the presence of what is loathsome & what is not — cutting himself off from both, he remains equanimous, alert, & mindful.

Now, with what purpose should a monk remain percipient of loathsomeness in the presence of what is not loathsome? 'Don't let passion arise within me in the presence of things that excite passion.' With this purpose should a monk remain percipient of loathsomeness in the presence of what is not loathsome.

And with what purpose should a monk remain percipient of unloathsomeness in the presence of what is loathsome? 'Don't let aversion arise within me in the presence of things that excite aversion'...

And with what purpose should a monk remain percipient of loathsomeness in the presence of what is not loathsome & what is? 'Don't let passion arise within me in the presence of things that excite passion. Don't let aversion arise within me in the presence of things that excite aversion'...

And with what purpose should a monk remain percipient of unloathsomeness in the presence of what is loathsome & what is not? 'Don't let aversion arise within me in the presence of things that excite aversion. Don't let passion arise within me in the presence of things that excite passion'...

And with what purpose should a monk — in the presence of what is loathsome & what is not — cutting himself off from both, remain equanimous, alert, & mindful? 'Don't let passion — in any object, in any place, in any amount — arise within me in the presence of things that excite passion. Don't let aversion — in any object, in any place, in any amount — arise within me in the presence of things that excite aversion. Don't let delusion — in any object, in any place, in any amount — arise within me in the presence of things that excite delusion.' With this purpose should a monk — in the presence of what is loathsome & what is not — cutting himself off from both, remain equanimous, alert, & mindful.

— AN 5.144

And what is right speech? Abstaining from lying, from divisive speech, from abusive speech, & from idle chatter: This is called right speech.